2205双相不锈钢管焊缝韧度分析

Analysis for toughness of 2205 duplex stainless steel pipe welds

2205双相不锈钢具有优异的力学性能和耐腐蚀性能,广泛用于运输、石油、天然气、海洋和化工等行业。与普通奥氏体不锈钢相比,双相不锈钢焊接有许多特点,被公认为是一种较难焊接的材料。某天然气集输管道最高操作压力13.3 MPa,最低操作温度-30℃,对韧度提出了较高的要求。对该高压天然气管道钢管纵、环焊缝的冲击韧度和断裂韧度(CTOD)进行了试验、分析。结果表明,纵焊缝(SAW焊接方法)的冲击韧度和断裂韧度比环焊缝(TIG+SMAW焊接方法)明显好。其主要原因是采用的填充金属不同,以及因热输入量差异、焊后固溶处理与否而引起显微组织中两相比例的差异造成的。

2205 duplex stainless steel possesses favorable mechanical properties and good corrosion resistance,and is applied wildly in transport,oil and natural gas,ocean and chemistry industry,etc.Compared to general austenitic stainless steel,duplex stainless steel is its difficult to weld.One natural gas the maximum operation pressure in one collection pipe of natural gas trausport is 13.3 MPa and still generally considered as material which are minimum operation temperature is-30℃,and very high toughness was required for the pipe welds.The Charpy impact toughness and fracture toughness(CTOD)of longitudinal welds(used SAW methods) and girth welds(used GTAW+SMAW methods) of 2205 duplex stainless steel pipe used for high pressure nature gas transport were tested and analyzed.The results show that the impact toughness and fracture toughness of longitudinal welds is better than that of the girth weld markedly.The main reason of these results is concern with difference of filler metal and microstructure phase ratio caused by difference heat input and postweld heat treatment.